贵州省开阳县斜坡地质灾害孕灾因子敏感性分析

Sensitivity analysis of disaster-pregnant environmental factors for slope geological hazards in Kaiyang County, Guizhou Province

  • 摘要: 开阳县地质条件复杂,区内山地灾害频发,在进行野外地质灾害调查的基础上,选取高程、坡度、坡向、工程岩组、斜坡结构、断层、水系、归一化植被指数(NDVI)8个影响因子作为斜坡地质灾害孕灾因子。基于GIS平台,采用确定性系数模型(CF)进行开阳县斜坡地质灾害孕灾因子敏感性分析,并通过敏感性指数(E)分析各因子对开阳县斜坡地质灾害的敏感性大小。结果表明:在高程515~993 m、坡度20°~50°、坡向为东南、西和西北向、软质岩组、顺向坡地区、距断层1 000 m以内、距河流800 m以内、NDVI值处于-0.098~0.181的区域,为开阳县地质灾害敏感区;坡度、岩性、坡向、距河流距离、距断层距离、高程6个因子为开阳县地质灾害的主要控制因素,NDVI和斜坡结构具有较低的敏感性;进一步分析表明,NDVI敏感程度很可能受高程1 288~1 664 m区间和北向坡向限制;斜坡结构敏感性主要受坡向东、西2个方向限制。研究成果可为开阳县地质灾害的防灾减灾工作提供参考。

     

    Abstract: The geological conditions are complex in Kaiyang County, and geological disasters occur frequently. On the basis of field geological hazard investigation, 8 factors including elevation, slope, slope direction, engineering petrofabric, slope structure, fault, drainage and NDVI value are selected as the disaster-pregnant factors of slope geohazards. Based on the GIS platform, and by using the certainty factor model(CF) and the sensitivity-exponential(E), susceptibility of these 8 factors are researched. The results show that the areas with elevation from 515 to 993 m, the slope degree from 20° to 50°, the aspect of the west, the northwest and the southeast, soft rock group, the consequent slope area, the distance from fault and rivers within 1 000 m, 800 m respectively and the NDVI value in -0.098 to 0.181 are sensitive areas of geohazards. Compared with the slope structure and the NDVI value which showed lower sensitivity, the others, slope, lithology, aspect, the distance from fault and rivers and elevation are the main control factors of the area. The further discussion results show that the sensitivity of the NDVI value is likely to be restricted by the elevation range of 1 288-1 664 m and the aspect of the north, and the sensitivity of the slope structure is limited by the aspect of east and west. The research results can provide reference for the prevention and reduction of geohazards in Kaiyang County.

     

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